Timing of ornaments in the theme of Beethoven's Paisiello variations: Empirical data and a model

Musicians have to make many interpretive decisions when performing a piece. For example, the grace note, a one-note musical ornament, has no precise duration written in the score; it has to steal its duration from either the preceding or following melody notes. There were several empirical questions this study sought to answer: What duration are grace notes given? Does this vary depending upon musical context or individual preferences? And, are their durations taken from the preceding or subsequent melody note, or is time added? In an experiment, 16 professional pianists performed 3 musical fragments (from a Beethoven Theme) 'with' and 'without' grace notes in 7 different tempi. The timing of the grace notes was found not to be proportional to changes in global tempo for most, but not all performers, which replicates earlier studies. In the majority of cases increases in bar duration were matched by relative increases in grace note duration that were smaller than predicted by a proportional tempo model, with a minority of subjects performing grace notes with fixed duration over tempo. In most cases, grace note duration was 'stolen' from the preceding melody note, with a small contribution from the following (main) note, and with minimal disturbance to local tempo. Conversely, where grace notes were played as appoggiatura, the main source of their duration was the main note. The type of grace note performed depended both on its musical context and on individual differences between performers. A model of grace note duration is proposed to account for these results